JavaScript is disabled for your browser. Some features of this site may not work without it.

Estimating treatment coverage in South African ART clinics based on the time trend of the CD4 count distribution at ART initiation and a dynamical epidemiological model

Mazinu, Mikateko Cynthia (2014-04)

Thesis (MSc)--Stellenbosch University, 2014.

Thesis

ENGLISH ABSTRACT: HIV treatment coverage is currently inferred by dividing the number of people
alive and on antiretroviral treatment (ART) by the number of individuals
eligible for treatment, and estimates of these numbers are often made using
dynamical epidemiological model. However, this approach ignores data on the
distribution of CD4 cell counts at the time of ART initiation, and hence the inferred treatment coverage may be inconsistent with these CD4 count data.
Here, we present a more inclusive method to estimate treatment coverage by
incorporating the time trend of the CD4 count distribution at ART initiation
in the dynamic epidemiological model. Data analysis of a cohort of 61 398 HIV
infected adult patients who initiated treatment at eight South African ART
clinics between 2004-2009 was conducted. Next, we used the results of the
statistical analysis to adjust the parameters in the epidemiological model that
governs the rate at which people from different CD4 cell count levels initiate
ART. Lastly, we calibrate the model to reproduce the number of people alive
and on ART. More than 80% of individuals started treatment very late, with CD4 count
<200 cells/ L. A maximum of three years were delayed treatment after being
eligible in all clinics involved in this study. The treatment coverage reached
61% in the eight clinics in our study. Methods to estimate ART coverage
should make maximal use of CD4 cell count data at ART initiation, which
may help to improve accuracy of the coverage estimates.